PHASE-COUPLED LASER ASSEMBLY AND METHOD FOR PRODUCING A PHASE-COUPLED LASER ASSEMBLY
20210273400 · 2021-09-02
Inventors
Cpc classification
H01S5/026
ELECTRICITY
H01S5/0071
ELECTRICITY
H01S2301/18
ELECTRICITY
H01S5/5027
ELECTRICITY
International classification
H01S5/026
ELECTRICITY
Abstract
A laser device is provided which comprises a common waveguide layer and a plurality of laser bodies, wherein each of the laser bodies has an active region configured for generating coherent electromagnetic radiation. The laser bodies are arranged side by side on the common waveguide layer, wherein the laser bodies are directly adjacent to the common waveguide layer. In particular, the laser bodies are configured to be phase-coupled to each other via the waveguide layer during operation of the laser device.
Furthermore, a method for producing such a phase-coupled laser device is provided.
Claims
1. A laser device comprising a common waveguide layer and a plurality of laser bodies, wherein the laser bodies each comprise an active zone configured to generate coherent electromagnetic radiation, the laser bodies are arranged side by side on the common waveguide layer, the laser bodies are directly adjacent to the common waveguide layer, and the laser bodies are phase-coupled to each other via the waveguide layer during operation of the laser device.
2. The laser device according to claim 1, wherein the laser bodies and the common waveguide layer are of monolithic form.
3. The laser device according to claim 1, wherein each of the laser bodies has a sublayer directly adjacent to the common waveguide layer, the sublayers and the common waveguide layer being formed from the same material at least at their transition region.
4. The laser device according to claim 1, which has a coupling layer comprising a plurality of coupling structures, wherein the coupling layer are arranged on a rear side of the common waveguide layer facing away from the laser bodies, and in a plan view of the common waveguide layer, the coupling structures are covered by the laser bodies.
5. The laser device according to claim 4, wherein the coupling structures extend into the common waveguide layer and are formed to be radiation-reflective with regard to the electromagnetic radiation generated by the laser bodies during operation of the laser device.
6. The laser device according to claim 1, wherein, in operation of the laser device, a lateral distance between adjacent laser bodies is m.Math.λ/n, where m is an integer, λ is the wavelength of radiation coupled into the common waveguide layer and n is the refractive index of the common waveguide layer.
7. The laser device according to claim 1, wherein electrically controllable active elements are integrated or formed in the common waveguide layer, the active elements being configured for locally adjusting the refractive index of the common waveguide layer.
8. The laser device according to claim 1, wherein the waveguide layer comprises a first sublayer, a second sublayer and an active region arranged therebetween, the active region being located in the coupling path of the waveguide layer.
9. The laser device according to claim 8, wherein the active region is configured to generate electromagnetic radiation and the common waveguide layer additionally serves as an optical amplifier.
10. The laser device according to claim 8, wherein the common waveguide layer has an active region, the active region being formed as an active quantum well layer of a Wannier-Stark modulator which, during operation of the laser device, brings about a change in the refractive index of the common waveguide layer as a result of an applied electric field.
11. The laser device according to claim 1, wherein the laser bodies are arranged at least in a row on the common waveguide layer, and at its edge the row has a guiding laser body which is configured in such a way that the electromagnetic radiation emitted by the guiding laser body is coupled out of the guiding laser body exclusively in the direction of the common waveguide layer, propagates along the common waveguide layer and stimulates the other laser bodies to emit phase-coupled electromagnetic radiation.
12. The laser device according to claim 11, wherein the guiding laser body arranged at the edge predetermines the phase of the radiations emitted by the laser bodies of the same row or column, the guiding laser body being free of a radiation-transmissive aperture on its surface facing away from the common waveguide layer.
13. The laser device according to claim 1, wherein the laser bodies form a plurality of rows and columns of laser bodies on the common waveguide layer, and with the exception of at most one laser body arranged at the edge, each of the laser bodies of the same row or column has a radiation-transmissive aperture facing away from the common waveguide layer.
14. The laser device according to claim 1, further comprising a first electrode, a third electrode, and a second electrode disposed between the first electrode and the third electrode, wherein the first electrode and the third electrode are assigned to a first electrical polarity of the laser device, the second electrode is assigned to a second electrical polarity different from the first polarity, the first electrode and the second electrode are configured for electrically contacting the laser bodies, and the second electrode and the third electrode are configured for electrically contacting the common waveguide layer.
15. The laser device according to claim 1, wherein the common waveguide layer has at least one side surface which is provided with a radiation-reflecting mirror layer.
16. The laser device according to claim 1, wherein the common waveguide layer has at least one side surface provided with a radiation absorbing absorber layer.
17. A laser device comprising a common waveguide layer, a plurality of laser bodies and a common carrier, wherein the plurality of laser bodies each comprise an active zone configured to generate coherent electromagnetic radiation, the plurality of laser bodies are arranged side by side on the common waveguide layer, the plurality of laser bodies are directly adjacent to the common waveguide layer, the plurality of laser bodies are phase-coupled to each other via the waveguide layer during operation of the laser device, and the common waveguide layer is located in the vertical direction between the common carrier and the plurality of laser bodies.
18. A method for producing the laser device according to claim 1, comprising: providing the common waveguide layer; forming a coherent laser body composite directly on the common waveguide layer; and structuring the coherent laser body composite into a plurality of laterally spaced laser bodies on the common waveguide layer.
Description
[0034] Further embodiments and further developments of the laser device or of the method for producing the laser device will become apparent from the exemplary embodiments explained below in connection with
[0035]
[0036]
[0037]
[0038]
[0039] Identical, equivalent or equivalently acting elements are indicated with the same reference numerals in the figures.
[0040] The figures are schematic illustrations and thus not necessarily true to scale. Comparatively small elements and particularly layer thicknesses can rather be illustrated exaggeratedly large for the purpose of better clarification.
[0041] Each of
[0042]
[0043] The laser bodies 2 and the common waveguide layer 1 can be of one-piece or monolithic design. The laser bodies 2 may each have a sublayer 24 immediately adjacent to the common waveguide layer 1, which has the same material as the common waveguide layer 1 at least in a transition region between the sublayer 24 and the waveguide layer 1. For example, the sublayers 24 of the laser bodies 2 and the common waveguide layer 1 may be formed from a single piece. In particular, there are smooth transitions between the sublayers 24 and the common waveguide layer 1. For example, there is no clear interface, in particular no clearly detectable interface between the common waveguide layer 1 and the laser bodies 2 or between the common waveguide layer 1 and the sublayers 24 of the laser bodies 2.
[0044] The laser bodies 2 and the common waveguide layer 1 are further considered to be of one-piece or monolithic design if the laser bodies 2 are in particular directly applied to the common waveguide layer 1. For example, there is no bonding layer, in particular no adhesive layer, glue layer or solder layer, in the vertical direction between the laser bodies 2 and the waveguide layer 1. This is shown schematically, for example, in
[0045] Each of the laser bodies 2 has a semiconductor body 2H. In particular, the semiconductor body 2H has a first semiconductor layer 21 of a first charge carrier type, a second semiconductor layer 22 of a second charge carrier type different from the first charge carrier type, and an active zone 23 arranged between the semiconductor layers 21 and 22. In operation of the laser device 10, the active zone 23 is particularly configured to generate coherent electromagnetic radiation. In particular, the active zone 23 is a pn-junction zone. The first semiconductor layer 21 may be n-conductive. The second semiconductor layer may be p-conductive. However, it is possible that the first semiconductor layer 21 is p-conductive and the second semiconductor layer 22 is n-conductive.
[0046] The laser bodies 2 each have a first mirror arrangement 71 facing away from the waveguide layer 1 and a second mirror arrangement 72 facing towards the waveguide layer 1. In particular, the first mirror arrangement 71 and the second mirror arrangement 72 form a laser resonator 7 of the laser body 2. The mirror arrangements 71 and 72 may be Bragg mirrors, in particular electrically conductive Bragg mirrors, or Bragg mirrors made of semiconductor materials. It is possible that the semiconductor body 2H, the first mirror arrangement 71, the second mirror arrangement 72, the sublayer 24 and/or the waveguide layer 1 are based on the same semiconductor compound material.
[0047] The second mirror arrangement 72, which is arranged in the vertical direction between the active zone 23 and the common waveguide layer 1, is in particular formed to be partially transparent to radiation. In particular, the second mirror arrangement 72 is formed to be at least partially transparent to the radiation S generated in the active zone 23 during operation of the laser device 10, so that the radiation S generated by the active zone 23 can be coupled through the second mirror arrangement 72 into the common waveguide layer 1. It is possible that the second mirror arrangement 72 has a lower reflectivity than the first mirror arrangement 71. Alternatively or additionally, it is possible that the second mirror arrangement 72 has a reflectivity for the radiation generated in the active zone 23 of at most 99%, 95%, 90% or of at most 80%, for instance between 50% and 99% inclusive, or between 60% and 95% inclusive, or between 60% and 80% inclusive.
[0048] According to
[0049] Deviating from this, it is possible that the insulation layer 8, in particular the first insulation layer 81, is replaced by an electrically conductive layer. In this case, the current can first be impressed over the entire surface of the laser body 2 and guided to the center by deeper-lying layers. The deeper-lying layers can be oxidized layers in the form of an aperture which narrow the current path from the outside. Alternatively or additionally, the deeper-lying layers can be doped, in particular highly doped current expansion layers located above and/or below the first mirror arrangement 71.
[0050] According to
[0051] The laser device 10 has a coupling layer 3 on the rear side 1R of the waveguide layer 1. The coupling layer 3 has a plurality of coupling structures 30. In particular, the coupling structures 30 are local vertical elevations of the coupling layer 3 that extend into the common waveguide layer 1. The coupling structures 30 may be formed to be radiation reflective. For increasing the reflectivity of the coupling structures 30, each of them may be provided with a radiation-reflecting cover layer 31. The cover layer 31 can be formed from a highly reflective material, such as aluminum, silver, palladium or platinum. If the coupling layer 3 is formed from an electrically conductive material, the coupling layer 3 can simultaneously serve as a contact layer, in particular as a second electrode 62 or third electrode 63 of the laser device 10.
[0052] Alternatively, it is possible that the cover layer 31 is not an electrical contact layer. The cover layer 31 is in particular an optically active layer which couples a part of the horizontally running mode into the laser body 2 or into the laser bodies 2. In particular, the cover layer 31 and the waveguide layer 1 have different refractive indices.
[0053] In particular, the coupling layer 3 and/or the second contact layer 62 and/or the third electrode 63 directly adjoin/s the waveguide layer 1 at least in places. In the areas of the coupling structures 30, the cover layer 31 can be arranged in the vertical direction between the waveguide layer 1 and the associated coupling structure 30.
[0054] If the cover layer 31 is formed as an electrical contact layer, an electrical contact resistance between the waveguide layer 1 and the cover layer 31 can be lower than an electrical resistance between the waveguide layer 1 and the coupling layer 3. As a result, it can be achieved that charge carriers are preferably impressed via the cover layer 31 into the waveguide layer 1 and thus centrally into the laser bodies 2. It is possible that the cover layer 31 is configured for electrically contacting active elements 1A, which are integrated or formed in the waveguide layer 1, for example.
[0055] In top view, each of the laser bodies 2 may cover, in particular completely cover, at least one coupling structure 30. It is possible that in top view, the coupling layer 3 does not have a coupling structure 30 that is not covered by one of the laser bodies 2. It is also possible that each of the laser bodies 2 cover a single coupling structure 30 in top view.
[0056] According to
[0057] According to
[0058] According to
[0059] Preferably, the coupling structure 30 is arranged centrally below an associated laser body 2. If electromagnetic radiation S is generated in the active zone 23, this can be coupled into the waveguide layer 1 and deflected in lateral directions at the associated coupling structure. The geometry of the coupling structure 30 may be selected such that the coupled electromagnetic radiation S is deflected in a desired lateral direction. For example, the coupling structure 30 has the shape of a pyramid or the shape of a cone. According to
[0060] The exemplary embodiment shown in
[0061] With the active region 13, the common waveguide layer 1 additionally serves in particular as an optical amplifier. With the active region 13 and the sublayers 11 and 12, the waveguide layer 1 has, in particular, a diode structure which, in operation of the laser device 10, is configured for generating or amplifying electromagnetic radiation. According to
[0062] The exemplary embodiment shown in
[0063] The second electrode 62 may have a contiguous contact layer 62, which is arranged in particular in the free areas Z along lateral directions between the laser bodies 2. It is possible for the second electrode 62 to have a plurality of laterally spaced contact layers 62, wherein the contact layers 62 are formed to be individually contactable. Using the second electrode 62, the stationary wave field formed in the waveguide layer 1 can be electrically amplified. Alternatively or additionally, it is possible that the refractive index, in particular the local refractive index, of the waveguide layer 1 can be changed by selectively applying an electrical voltage to the second electrode 62, which in particular has a plurality of individually contactable contact layers 62.
[0064] As a further difference to
[0065] The exemplary embodiment shown in
[0066] In contrast to
[0067] The exemplary embodiment shown in
[0068] In particular, the coupling layer 3 has a guiding coupling structure 30L, which is covered, in particular completely covered, by the guiding laser body 2L in top view. In contrast to the other coupling structures 30, the guiding coupling structure 30L has a larger vertical height and a larger cross-section. In particular, the guiding coupling structure 30L can extend through the second sublayer 12 and the active region 13 of the waveguide layer 1. Preferably, the guiding coupling structure 30L is configured to redirect the coupled radiation S in only one lateral direction, rather than in two opposite lateral directions. For example, the guiding coupler structure 30L is not arranged centrally below the guiding laser body 2L, but offset with respect to a central axis of the guiding laser body 2L, so that the radiation generated by the guiding laser body 2L is deflected in one lateral direction in a targeted manner.
[0069] In contrast to
[0070]
[0071] The concept explained in connection with
[0072] Using a phase-coupled, monolithically integrated and in particular single-mode laser device, the radiation direction or the out-coupling direction of the laser device from a plurality of laser bodies are controllable by electrical signals, as a result of which dynamic control of geometric patterns is achievable. In particular, the laser device is implemented as a single semiconductor chip without optics with optional control of the periodicity of a pattern to be imaged and/or with optional control of its radiation direction by electrical signals without using moving parts, for instance without using moving optical parts.
[0073] This application claims the priority of the German patent application DE 10 2018 123 320.5, the disclosure content of which is hereby included by reference.
[0074] The invention is not restricted to the exemplary embodiments by the description of the invention made with reference to the exemplary embodiments. The invention rather comprises any novel feature and any combination of features, including in particular any combination of features in the claims, even if this feature or this combination is not itself explicitly indicated in the patent claims or exemplary embodiments.
LIST OF REFERENCE SIGNS
[0075] 10 Laser device
[0076] 10V Front side of the laser device
[0077] 10R Rear side of the laser device
[0078] 1 Common waveguide layer
[0079] 11 First sublayer of the waveguide layer
[0080] 12 Second sublayer of the waveguide layer
[0081] 13 Active region of the waveguide layer
[0082] 1 Active element
[0083] 1V Front side of the waveguide layer
[0084] 1R Rear side of the waveguide layer
[0085] 1S Side surface of the waveguide layer
[0086] 1X First subregion the waveguide layer
[0087] 1Y Second subregion the waveguide layer
[0088] 2 Laser body
[0089] 21 First semiconductor layer
[0090] 22 Second semiconductor layer
[0091] 23 Active zone
[0092] 24 Sublayer of the Laser body
[0093] 2H Semiconductor body of the laser body
[0094] 2L Guiding laser body
[0095] 3 Coupling layer
[0096] 30 Coupling structure
[0097] 30L Guiding coupling structure
[0098] 31 Reflective cover layer
[0099] 4 Radiation non-transmissive layer
[0100] 41 Mirror layer
[0101] 42 Absorber layer
[0102] 6 Radiation transmission range
[0103] 60 Aperture
[0104] 61 First electrode/first contact layer
[0105] 62 Second electrode/second contact layer
[0106] 63 Third electrode/third contact layer
[0107] 7 Laser resonator
[0108] 71 first mirror arrangement
[0109] 72 second mirror arrangement
[0110] 8 Insulation layer
[0111] 81 First insulation layer
[0112] 82 Second insulation layer/passivation layer
[0113] 9 Common carrier
[0114] 90 Rear-side cover layer
[0115] H Brightness
[0116] L Lateral distance between adjacent laser bodies
[0117] S Radiation
[0118] W Angle
[0119] Z Intermediate region